Rolled section for framing in mines and supporting structure for utilizing same



Dw 1936. H. ToussAlN 2,062,686

. ROLLED SECTION FOR FRAMING INES AND SUPPORTING STRUC E FOR ING SAME Filed 2 Sheets-Sheet l UTI 1 n. 19, 1935 Dec. 1, 1936. H; ToussAlN'i' ROLLED SECTION FOR FRAMING IN MINES AND Filed Jan. 19, 1933 M4 fm Patented Dec. 1, 1936 UNITED STATES ROLLED SECTION FOR FRAIVIING IN MINES AND SUPPORTING STRUCTURE FOR UTI- LIZlING SAME Heinrich Toussaint, Berlin-Lankwitz, Germany Application January 19, 1933, Serial No. 652,523 In Germany January 22, 1932 5 Claims.

The object of the invention is an open channel-shaped rolled section for iron framing in mines and also the supporting structure for its use.

The invention is based on the knowledge that in pit workings, in contrast to superstructures, the supporting members are frequently stressed beyond their elastic limit and therefore the question of bending out of shape must be taken into account. Moreover, as in mining it is often not only a question of purely vertical pressures but of lateral pressure components acting at the same time, the stress acts in all directions of the cross-section of the section iron, so that not only the resistance of the supporting member against vertical pressure but also the lateral moments of resistance and moments of inertia are of importance. The sections used heretofore in pit framing often collapse for the reasons stated about the weak yy axis shown on the drawings forming part of this application. This is a considerable drawback, because it renders it difiicult to adopt the usual methods of re-straightening the sections.

According to the present invention, these drawbacks are overcome by giving the pit framing section the form of a trough iron. In order to insure a large resistance in the vertical direction and at the same time a large resistance to vertical crippling, the section according to the invention is given resisting moments and moments of inertia which are equal or approximately equal with respect to both axes. In order to preclude the tendency to laterally collapse which, as already mentioned, makes the straightening of the section much more difficult, the rolled section according to the invention may be of such a profile that the moment of resistance and inertia according to the y-y axis is even greater than the moment of resistance and moment of inertia with reference to the :n-a: axis shown on the drawings, this being obtainable by but a slight extra expenditure of material. Specifically, the rolled section according to the invention is so proportioned that the cross-sectional areas of the flanges or booms are equal or approximately equal, so that the neutral axis of the section lies in the centeror approximately in the center between the two flanges. On the other hand, the two bottom flange surfaces which, in order to obtain the maximum of resisting moment with the smallest amount of material must be half as long and of the same thickness as the top flange, may be shorter and thicker but equal or approximately equal in area to the top flange. Thus, restraightening and in fact the bending of the section at all into an arched or curved shape becomes considerably easier. In cases like arched framings and curved cap pieces where, in order to obtain the most favorable arched shape from a static point of view, a higher moment of inertia is desirable towards the side, the profile according to the invention is so pro"- portioned that the sum of the bottom flange faces is greater than the upper flange area. Further the entire profile can be 50' extended that the moment of resistance and inertia with reference to the 11-11 axis is many times the moment of resistance and inertia with reference to the :cm axis, this being easily attainable by a slight extra expenditure of material in the flanges. In order to impart to the section a greater resistance to bending and to spreading apart, according to the invention the corner curves where the webs run into the flanges are of gradual shape and are preferably in the form or substantially in the form of a cubic parabola. The form of the cubic parabola is determined for example by the bounding lines of the moment areas which would result from loading the various portions of the profile (flanges and webs) after the manner of a beam fixed at one end. Preferably, the straight webs of the section are at an angle just slightly in excess of degrees, with respect to the flanges. Further, the resistance to bending may be increased by stiffening the section at various places in its open side by fiat irons, plates or similar members imparting rigidity.

According to the invention, trough-irons and similar channel-shaped rolled sections may be used for any purpose in pit framing, such as lagging, cap or cornice pieces, stretchers, props, stanchions, polygonal and arched roof supports. In particular, the advantages of the invention are felt in connection with circular structures, horse-shoe shaped arches and polygonal framing. In arched framing two ends of the sections are joined together by fitting one over the other.

The invention also contemplates the provision of various forms of pit framing whereby the advantages of the section according to the invention can be utilized to the full. Thus for example, the invention proposes to reinforce the supporting structure by fitting special reinforcing members over the frame profile. The advantages of the section according to the invention may be effectively increased still further by arranging tension members between the ends of the arched cap or inside the arched frame, so that the resistance in vertical direction is multiplied. These tension members may consist of fiat irons, round sections, hoop iron or sections of any profile and may be adjustable in length. Preferably, their length is such that they only come into effect after the roofing material has experienced a certain deflection. Thus the increase of stability produced by the tension members only comes into effect when the pressure of the earth has commenced to act to a certain extent upon the roof. Finally, the invention provides various other structures for supporting pit roofs, and these will be clearer by referring to the accompanying drawings in conjunction with the explanatory text.

In the drawings, Figures 1 to 6 show some forms of trough iron sections such as are used according to the proposal of the present invention for pit roof supports, whilst Figs. 7 to 13 illustrate various practical examples of the applications of the rolled section according to the invention.

Figure 1 shows a trough-iron section with arched webs I while in Figs. 2 to 6, the webs are straight.

In the shape according to Figs. 1 and 2, the bottom flanges 2 are equal in total length and in area to the top flange or bridge-work area 3, so that the resisting moment with reference to the a::c axis is a maximum with regard to the vertical stress.

In the shape according to Fig. 3, the bottom flanges 2 are shorter and thicker but the area is equal to that of the upper flange or bridge-work area 3.

As will be seen from the shapes according to Figs. 4 and 5, the flanges 2 and 3 form with respect to the straight webs I, angles on and B which are just slightly greater than 90 degrees. This reduces the amount of leverage a, so that the section is able to offer a greater resistance to expanding or spreading. At the same time the corner curves between the flanges 2 and 3 and the webs I run out gradually preferably according to a cubic parabola. Figure 5 shows a section which is highly suited for taking up lateral stresses.

Fig. 6 shows the union of two trough-iron sections 4 and 5 to form a box girder.

Figures '7 and 8 show the use of the rolled section in gallery framing. In the open channel of the cap or cornice 6, which in Fig. 8 has an arched shape, there are fixed transverse members I which limit the thrust of the props 8. In Fig. 8, there are shown abutment members 9 whereby the cap 6 is firmly wedged against the wall-face. This abutment 9 may consist of section iron, double T-iron, U-iron or trough-iron.

In Fig. 9, the tension members 2|] are arranged inside the ring [9- at places of highest pressure. These tension members 28 may function at the same time as compression struts by making them of suitable section iron. The idea may likewise be applied to horse-shoe arches.

Figs. 10 to 12 show the application of the rolled section according to the invention to arched pit framing. The arch 2! is reinforced at the points of intense pressure by providing special members 22. The tying of the arch is brought about either by fitting a channel-shaped. section member 23 over it, or as shown in Fig. 11, by pushing the two adjacent ends 24 and 25 of the section over each other.

As illustrated in Fig. 12, the section-iron may be arranged either with the channel towards the inside of the gallery, as shown at the left-hand side, or with the channel outside, as indicated at the right-hand side. As indicated by the line 26 representing the air current, the right-hand construction has the advantage that it offers small resistance to the air draught. 21 and 28 denote fiat bars and plates respectively which are inserted in the section and serve for stiffening. The flat bars 21 and plates 28 may be inserted individually or jointly in the section, according to conditions or to the desired degree of stiffening, Fig. 12 showing both members applied to a single section. Of course, these stiffening means are applicable to all examples previously shown and described. 29 denotes a stay which may rest either directly on the lower flanges of the section or, as shown at the right-hand side, may rest on specially fitted parts 3!! to reinforce the frames relative to one another.

Fig. 13 illustrates an example of the application of the invention to polygonal framing. 3| denotes the polygon stempel. The long stempel 32 is provided with a tension member 33 which, in conjunction with the section iron 34 acts as a strut frame just as in the example according to Fig. 9.

I claim:

1. A rolled ferrous mine frame-member, comprising a symmetrical body portion, trough-like in cross-section, provided with laterally extending flanges, said flanges being equal in cross-sectional area and having a total cross-sectional area equal to that of the bridge-work area.

2. A rolled ferrous mine frame-member, comprising a symmetrical body portion, trough-like in cross-section, provided with laterally extending flanges, said flanges being thicker than and their cross-sectional length less than that of said body portion, but their total cross-sectional area equal to that of the body portion.

3. A rolled ferrous mine frame-member for forming self-contained circular and archedmine frames, comprising a symmetrical body portion, trough-like or U-shaped in cross-section, provided with laterally extending flanges, said frames being formed of a plurality of said members having body portions of equivalent static values and forming butt-joints with their ends, said joints being bridged and reinforced by anequivalent section member possessing a trough-like or U- shaped cross-section and adhering with its sides to the sides of the members embraced by it.

4. A rolled ferrous mine frame-member, comprising a symmetrical body portion, trough-like in cross-section, provided with lateral flanges, said flanges being equal in cross-sectional area and having a total cross-sectional area greater than that of the bridge-work area.

5. A rolled ferrous mine frame-member, comprising a symmetrical body portion, trough-like in cross-section, provided with laterally extending flanges, said flanges being equal in crosssectional area and having a total cross-sectional area at least equal to that of the bridgework, the sides of said body portion forming webs running into the bridge-work and said lateral flanges in curved corners shaped like a cubic parabola and increasing in thickness approximately from the center of the webs towards the bridgework and the lateral flanges.

HEINRICH TOUSSAINT. 

